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Physical Performance and Antioxidants
Published in Datta Sourya, Debasis Bagchi, Extreme and Rare Sports, 2019
Several studies demonstrate that ROS impair insulin-mediated glucose uptake and storage by disrupting signaling control points, such as glycogen synthase kinase-3, Akt phosphorylation, and actin remodeling (Irrcher et al. 2009; Petersen et al. 2003). As mentioned above, muscle damage-induced oxidants suppress insulin-induced glucose uptake and glucose transporter 4 (GLUT4) translocation by impairing insulin receptor activation and PI3-K/Akt signaling (Aoi et al. 2012; Del Aguila et al. 2000). Dietary antioxidants can potentially improve the suppressed glucose metabolism resulting from muscle damage after exercise.
Pathological Evaluation and Biochemical Characterization of Peptide Receptors Other Than Somatostatin Receptors as Potential Tumor Targets for Radionuclide Diagnosis and Therapy
Published in Marco Chinol, Giovanni Paganelli, Radionuclide Peptide Cancer Therapy, 2016
Giuseppe Pelosi, Michelle Masullo, Giuseppe Viale
CCK and gastrin exist in different molecular forms, all deriving from prohormones processed to peptides of variable length, but characterized by the same five terminal amino acid sequences at the C-terminus extremity. They function as neurotransmitters in the central nervous system and as regulatory/growth factors in the gastroenteropancreatic tract and in the derived tumors (36). The best characterized CCK and gastrin receptors are CCK1 and CCK2 receptors (37–39), the former with low and the latter with high affinity for gastrin, but additional CCK receptors have been described (40). The binding of gastrin or CCK to their common cognate receptor triggers the activation of multiple signal transduction pathways that relay the mitogenic signal to the nucleus and promote cell proliferation. A rapid increase in the synthesis of lipid-derived second messengers with subsequent activation of protein phosphorylation cascades, including mitogen-activated protein kinase, is an important early response to these signaling peptides. Gastrin and CCK also induce rapid Rho-dependent actin remodeling and coordinate tyrosine phosphorylation of cellular proteins including the non-receptor tyrosine kinases p125fak and Src and the adaptor proteins p130cas and paxillin (reviewed by Rozengurt & Walsh, 2001) (41). CCK1 receptors are detectable in gallbladder and gastric smooth muscle and in the peripheral nervous system, especially in afferent vagal neurons and in the myoenteric plexus (35,42,43), whereas CCK2 receptors are distributed into the brain and epithelial cells of the gut and endocrine pancreas (42,44) and in normal C-cells of the thyroid (45).
Pulmonary Endothelium in Health and Viral Infections
Published in Sunit K. Singh, Human Respiratory Viral Infections, 2014
Nikolaos Manitsopoulos, Frantzeska Frantzeskaki, Anastasia Kotanidou, Stylianos E. Orfanos
The paracellular way refers to a route “around” the cell. The molecules that use this way are small, such as urea and glucose, and their transportation is size-selected, depending on their molecular radii (Mr), which cannot exceed 3 nm.1 The “continuous layer” of the endothelial structure is achieved through a complex set of junctional proteins forming tight junctions (TJs) and adherens junctions (AJs), giving shape to a zipper-like frame. Adherens junctions are formed mainly by vascular-endothelial (VE)-cadherin, a member of the cadherin family. These are single-span transmembrane glycoproteins. They mediate cell-to-cell adhesion in a calcium-dependent way.1 A potent disruptor of vascular permeability is vascular endothelial growth factor (VEGF). VE-cadherin maintains vascular permeability by binding to tyrosine kinase VEGF receptor 2 (VEGF-R2). In the presence of VEGF, the degradation of VE-cadherin is initiated and the AJs are disrupted.14,15 Tight junctions are formed by claudins, occluding and junctional adhesion molecules (JAMs). These three protein complexes bind zona occludens (ZO) to cytoplasmic signaling molecules and the actin cytoskeleton. AJs and TJs, composing the interendothelial junctions (IEJs) maintain vascular integrity via actin remodeling.1 Another type of connection between ECs is gap junctions (GJs). These are formed by hydrophilic transmembrane proteins called connexons (Cx), such as Cx37, Cx40, and CX43.1 Moreover, the paracellular pathway is affected by the interaction of ECs with ECM. Integrins are expressed by ECs and are bound to the ECM serving as protein receptors. The specific integrin binding sites of the ECM are named “focal contacts” or “focal adhesions.” Signaling pathways regulate paracellular permeability through a complex interaction between adhesive and counteradhesive forces, which adjust the opening and closing of the IEJs. The GJs signaling pathways also regulate the interactions between ECs and the ECM.1
A porcine ligated loop model reveals new insight into the host immune response against Campylobacter jejuni
Published in Gut Microbes, 2020
Nicholas M Negretti, Yinyin Ye, Lais M Malavasi, Swechha M Pokharel, Steven Huynh, Susan Noh, Cassidy L Klima, Christopher R Gourley, Claude A Ragle, Santanu Bose, Torey Looft, Craig T Parker, Geremy Clair, Joshua N Adkins, Michael E Konkel
In addition to immune-related proteins, components of the Arp2/3 complex, which facilitate actin rearrangement, were increased in abundance in the C. jejuni-inoculated loops. One of the key requirements for C. jejuni invasion of epithelial cells is activating the actin rearrangement and adhesive machinery. While the specific cell-type producing these proteins is not known, it is known that C. jejuni relies on actin reorganization to invade epithelial cells.31 However, given the apparent abundance of neutrophil-related proteins, an increase in actin remodeling proteins could also be a result of neutrophil migration into the intestine. This influx of neutrophils, and their killing associated antimicrobial proteins, was observed at the 12 hour and 30 hour time points. Thus, we propose that neutrophils drive intestinal inflammation and the initiation of diarrhea in C. jejuni-infected individuals.
Biochemical and immunocytochemical characterization of coronins in platelets
Published in Platelets, 2020
David R. J. Riley, Jawad S. Khalil, Khalid M. Naseem, Francisco Rivero
Platelets are anucleate fragments of megakaryocytes that play pivotal roles in hemostasis, thrombosis, wound healing and immunological processes. Platelets display a remarkable morphological plasticity. While in circulation they have a characteristic discoid shape, but are capable of undergoing profound changes upon adhesion to damaged blood vessel walls, transitioning to a spherical shape that extends filopodia and lamellipodia as the cell spreads and flattens [1]. This process is accompanied by secretion of granules and activation of integrins that support and consolidate the formation of a platelet aggregate. Remodeling of the cytoskeleton, formed by a network of actin filaments and a marginal ring of microtubules and associated proteins constitutes a crucial aspect of platelet function and is the result of multiple exquisitely integrated signaling cascades [2]. A plethora of proteins with various biochemical activities is responsible for the dynamics of actin remodeling during platelet activation, including actin nucleators like formins and the Arp2/3 complex and their regulators (WAVE, WASP), monomeric actin-binding proteins like profilin, β-thymosin and the cyclase-associated protein (CAP) and others like gelsolin, cofilin, and coronins [3–5].
Angiopoietin-1 accelerates restoration of endothelial cell barrier integrity from nanoparticle-induced leakiness
Published in Nanotoxicology, 2019
Jie Kai Tee, Magdiel Inggrid Setyawati, Fei Peng, David Tai Leong, Han Kiat Ho
In this study, we showed that Ang1 promotes the recovery of endothelial barrier (Figure 2) and prevents further endothelial leakiness caused by TiO2 NPs (Figure 3). In addition, our results revealed that the anti-permeability effect of Ang1 is mediated by the establishment of a direct physical interaction between endothelial cells and supported by a mechano-transduction phenomenon (Figure 4), thereby inhibiting the NanoEL effect. This NanoEL effect is mediated by the loss of VE-cadherin interaction between the cells and the subsequent phosphorylation of VE-cadherin at two tyrosine residues (Y658 and Y731) (Figure 1(D)). Furthermore, actin remodeling and microtubule acetylation facilitate the cells retraction, thereby creating a gap which we coined as the NanoEL effect. While leaky vessels may aid the passage of therapeutic NPs or drugs through the endothelial barrier (Matsumoto et al. 2016; Setyawati, Tay, and Leong 2014; Dewhirst and Secomb 2017), it is also important to note that a larger gap would also promote undesired molecules or cells to be transported across the dysregulated blood barrier. Hence, applications of NPs to enhance drug transport must achieve a tight balance in terms of the extent and duration of permeability. This is where the use of an anti-permeability factor in tandem could tighten the regulation of this intricate balance.